This invention relates to a fuel feed device for an internal combustion engine and more particularly to an improved arrangement for automatically supplying additional fuel under certain specific engine conditions and also for permitting manual override of this additional fuel supply to permit either the supply or the termination of the supply of additional fuel manually.
It is well known that the fuel requirements of an internal combustion engine vary widely during its various running conditions including starting, cold starting and cold running. Although it is possible to provide a single charge forming system that will supply the appropriate amount of fuel under all these conditions, the tailoring of the main fuel supply to suit all the conditions which the engine may encounter can render it quite complicated. Therefore, as disclosed in copending application entitled "Fuel Supply for Plural Cylinder Engine", Ser. No. 345,614, filed Apr. 14, 1989 and assigned to the Assignee of hereof, there is disclosed an improved supplemental fuel supply system for introducing fuel to the engine under specific running conditions. This supplemental fuel supply system is operated by an automatically controlled valve. Such arrangements have obviously great utility.
However, when the automatic control is incorporated there is always a danger that the automatic control may malfunction. Although arrangements have been provided for permitting enrichment in the event of such failure, these devices do no permit either enrichment or shutting off of the enrichment in the event the automatic control provides enrichment when it is not required due to some malfunction.
It is, therefore, a principle object of this invention to provide an improved fuel feel device for an internal combustion engine that is automatic in operation but which also has a manual override that will permit either the supply of additional fuel or the discontinuance of the supply of additional fuel manually.
It is a further object of this invention to provide a manual override for an automatic fuel supply service that permits the supply of additional fuel to be either initiated or discontinued regardless of the failure mode of the automatic system.